[coreboot-gerrit] Patch set updated for coreboot: 8830008 arm64: Add conditional read/write from/to EL3 assembly macros.
Patrick Georgi (pgeorgi@google.com)
gerrit at coreboot.org
Fri Apr 10 15:00:42 CEST 2015
Patrick Georgi (pgeorgi at google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/9538
-gerrit
commit 8830008e09a0bf7a4b0a1a2c3bed80115b198bc6
Author: Furquan Shaikh <furquan at google.com>
Date: Fri Nov 21 15:35:17 2014 -0800
arm64: Add conditional read/write from/to EL3 assembly macros.
Some registers are available only at EL3. Add conditional read/write functions
that perform operations only if currently we are in EL3.
BUG=chrome-os-partner:33962
BRANCH=None
TEST=Compiles and boots to kernel prompt.
Change-Id: Ic95838d10e18f58867b6b77aee937bdacae50597
Signed-off-by: Patrick Georgi <pgeorgi at chromium.org>
Original-Commit-Id: 62a0e324a00248dba92cb3e2ac2f4072d0e4e2a7
Original-Signed-off-by: Furquan Shaikh <furquan at google.com>
Original-Change-Id: Ia170d94adb9ecc141ff86e4a3041ddbf9045bc89
Original-Reviewed-on: https://chromium-review.googlesource.com/231549
Original-Reviewed-by: Aaron Durbin <adurbin at chromium.org>
Original-Tested-by: Furquan Shaikh <furquan at chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan at chromium.org>
---
src/arch/arm64/include/armv8/arch/lib_helpers.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/src/arch/arm64/include/armv8/arch/lib_helpers.h b/src/arch/arm64/include/armv8/arch/lib_helpers.h
index a804747..422b81a 100644
--- a/src/arch/arm64/include/armv8/arch/lib_helpers.h
+++ b/src/arch/arm64/include/armv8/arch/lib_helpers.h
@@ -214,6 +214,31 @@
104:
.endm
+/* Macro to read from a register at EL3 only if we are currently at that
+ level. This is required to ensure that we do not attempt to read registers
+ from a level lower than el3. e.g. SCR is available for read only at EL3.
+ IMPORTANT: if EL != EL3, macro silently doesn't perform the read.
+*/
+.macro read_el3 xreg sysreg
+ switch_el \xreg, 402f, 402f, 401f
+401:
+ mrs \xreg, \sysreg\()_el3
+402:
+.endm
+
+/* Macro to write to a register at EL3 only if we are currently at that
+ level. This is required to ensure that we do not attempt to write to
+ registers from a level lower than el3. e.g. SCR is available to write only at
+ EL3.
+ IMPORTANT: if EL != EL3, macro silently doesn't perform the write.
+*/
+.macro write_el3 sysreg xreg temp
+ switch_el \temp, 402f, 402f, 401f
+401:
+ msr \sysreg\()_el3, \xreg
+402:
+.endm
+
#else
#include <stdint.h>
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